This invention relates generally to optical interfaces for data communication and, more particularly, to optical interfaces which can be manufactured and aligned in a cost-effective manner, as well as to methods for aligning such optical interfaces.
Optical data communications technology has a number of advantages over wire technology. For example, bandwidth, data rate and response characteristics are superior to those of conventional wire technology. Optical technology is essentially immune to RFI (radio frequency interference) and EMI (electromagnetic interference) issues that plague wire technology. Shielding as in coaxial cables is not required, allowing the overall size and weight of systems to shrink.
Optical fiber telephone lines and world wide data links are replacing the bandwidth-limited wire technology. Likewise, optical technology, particularly optical interfaces for data communications, is highly desired in a variety of applications such as multi-component modules (MCMs), various printed circuit board (PCB) technologies, and integrated backplanes. Employing optical timing in radar transmit/receive modules to form phased array antennas is an objective in design of radar installations.
In such systems, electro-optical devices can be employed at the point of conversion from light to electronic transmission, and vice-versa. (As employed herein the term "light" is not limited to visible light, and includes optical wavelengths both above and below the range of visible light wavelengths). Electro-optical devices typically comprise semiconductor devices, which may be referred to as "chips" or "die." Examples of optical emitters or transmitters include light emitting diodes (LEDs), laser diodes, and arrays of these used in automobile tail light applications. An example of an optical receiver is a photodiode. The integration of such electro-optical devices within high density interconnect structures, including the use of adaptive lithography techniques to produce optical interconnects, is disclosed in aforementioned Wojnarowski et al., U.S. Pat. Nos. 5,562,838 and 5,737,458.
Problems associated with micro-optical alignment prevent the economical usage of optical technology. Generally, micro-optical alignment is an expensive hand tuning operation. Thus, what is limiting a great number of potential applications is the ability to correctly align an optical die to an optical path, such as is represented by an optical fiber or by a corresponding optical die, as well as the ability to interconnect an optical assembly to a backplane.